The generally accepted and accessible method of cytogenetic assessment of the mutagenic effect of factors of various nature is the micronucleus test. Now this test is one of the non-invasive methods of population survey, which are influenced by environmental pollution. Objective: to establish the characteristics of karyological indicators of buccal epithelium in children of patients with neonatal sepsis, whose parents constantly lived in different environmental conditions. Material and methods. To study this goal, a comprehensive examination of 260 newborns who underwent neonatal sepsis in 2015-2018 was carried out. A suggested feature of a comprehensive assessment of the long-term load on the body of parents of newborns of anthropogenic pollution of air, water and soil in the regions of the region was the proposed environmental risk coefficient (CER) taking into account the environmental situation in the regional centers. So, the first clinical group (the main one) included patients with neonatal sepsis, whose parents constantly lived for months with a CER of 2,0 or more and with an unfavorable ecological characterization of the regional center. The second group (comparisons) was formed by newborns with sepsis, whose parents lived permanently in areas with a low risk of adverse effects of these environmental factors on their bodies (CER<2,0). A micronuclear test of exfoliative buccal epithelium in patients with neonatal sepsis was performed and evaluated in the immunological laboratory of the Department of Pediatrics and Pediatric Infectious Diseases of the Bukovynian State Medical University according to the method of V.N. Kalaev. Results and its discussion. In the main group, children with a high risk of cytogenetic disorders significantly prevailed with a slight decrease in the quota of patients with low risk. So, in group I with a low risk of cytogenetic disorders there were 42,1 % of cases, with an average risk of 5,3 %, and with a high risk of 52,7 % of cases. In the comparison group, respectively, with a low risk of cytogenetic disorders there were 54,5 %, (P>0,05) cases, with an average risk of – 12,1 %, (P>0,05), and with a high risk of – 33,3 %, (P=0,05) cases. Conclusions. As a result of the karyological test of exfoliate buccal epithelium, it can be noted that in newborns of the main group, compared with children of the comparison group, cytogenetic disturbances and, in some cases, violation of cell kinetics in the form of proliferation and apoptosis were significantly more often detected. The accumulation index of cytogenetic disorders was also significantly higher in group I patients due to the predominance of patients with a high risk of cytogenetic disorders in them